Traction increaser apparatus for railway vehicles



cs. BRAUN 3,493,086

TRACTION INCREASER APPARATUS FOR RAILWAY VEHICLES Feb. 3, 1970 Filed Dec. 11, 1967 T T A M F T m m o N v v V W N R A M I? m mN OQN F N] N r 2? W g ml E W 50235 H w 555 m 1 N. M m $N m-N 0v x5558 4.. L h NW 2 mmsmmwma 3 H. E 4k 4 3 m k w 6528 9.55 m R 1, 1 :i s

United States Patent 3,493,086 TRACTION INCREASER APPARATUS FOR RAILWAY VEHICLES Giinter Braun, Furstenfeldbruck, Germany, assignor to I Knorr-Bremse G.m.b.H., Munich, Germany, a corporation of Germany Filed Dec. 11, 1967, Ser. No. 689,452 Claims priority, application Germany, Dec. 9, 1966,

U.S. Cl. 188-165 12 'Claims ABSTRACT OF THE DISCLOSURE An arrangement for automatically applying a force to raise a magnetic traction increaser device from its effective position to its ineffective position spaced above the rails in response to the positioning of the device in its effective position so that the device will immediately rise to its ineffective position when it is deenergized.

The present invention relates to a magnetic traction increaser apparatus for railway vehicles, more particularly, to an arrangement for facilitating the raising of the increaser device to its ineffective position when its use is no longer required.

In order to stop railway vehicles when they are travelling at high speeds its is necessary to apply high braking forces. However, it frequently occurs that during braking there is insufficient adhesion between the wheels of the vehicle and the rails to permit the desired rate of deceleration. There is then considerable danger of the braking forces causing the wheels to skid. In order to increase the adhesion, or traction, between the wheels and the rails various forms of forces or traction increaser devices have been proposed. Such devices have generally been electromagnetic in form and are positioned over the rails so that when energized they produce a strong magnetic attraction which is suflicient to draw the wheels to the rails with substantial force. As a result, the traction of the wheels is increased so that a greater braking force can be applied to the wheels without causing the wheels to skid. In addition, greater power may be applied to drive the wheels without causing skidding. Traction increaser devices were initially mounted from the frame of the vehicle to be positioned a short distance above the rail. While it is desired to position the device as close to the rail as possible there was the danger that the device would be torn loose or damaged by various dangers or obstructions along the tracks, i.e., crossings, switches and frogs,

particularly on curves or bends in the track.

In order to avoid such obstructions or any irregularities on the tracks, the increaser devices were initially mounted from the frame of the vehicle so as to be positioned a relatively large distance above the rail. This distance resulted in an air gap between the rails and the electromagnetic increaser which adversely affected its operation. It was then proposed to mount the increaser device from double-acting fluid pressure motors by which the device could be lowered to an effective position during starting or braking of a locomotive. The devices were generally provided with pre-tensioned springs which urged the device away from the rails with suflicient force to overcome the weight of the device.

However, these traction increaser devices were generally not satisfactory since the movement of the devices between their effective and ineffective positions were not properly controlled. Therefore, the increase in traction was not properly coordinated with the braking or driving of the locomotive.

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It is therefore the principal object of the present invention to provide a novel and improved magnetic traction increaser device for railway vehicles.

It is another object of the present invention to provide a novel and improved control mechanism for raising and lowering a magnetic traction increaser device between its effective and ineffective positions.

It is an additional object of the present invention to provide a supplemental force urging the traction increaser device toward its effective position in response to the movement of the device to its effective position.

The present invention is particularly adapted to a wheeled vehicle having wheels operating on a metallic supporting surface such as a railway locomotive of the steam, diesel, diesel electric or other type. Such vehicles are generally provided with a fluid pressure operated braking system. According to the present invention there may be provided a magnetic traction increaser device which is movable vertically between an effective position immediately above the rail and an ineffective position at a somewhat greater distance above the rail. The increaser device may be lowered to its effective position or raised to its ineffective position by double-acting fluid pressure motors which are connected to a source of fluid under pressure. There is also provided an electrical control circuit for controlling the operation of the fluid pressure motors. When lowered to its effective position, the magnetic device actuates an electric switch in the control circuit which applies fluid pressure to the pressure motors in a direction so as to urge the device upwardly away from its effective position. This force will assist in tearing away the device from the rail and will be almost equal to the magnetic force exerted by the device against the rail. This lifting force would not in any way obstruct the lowering of the device to its effective position. Thus, when the magnetic device is de-energized upwardly acting springs associated with the fluid motors will immediately raise the device to its ineffective position.

Other objects and advantages of the present invention will be apparent from the accompanying description when taken in conjunction with the drawing which illustrates schematically the electrical and fluid pressure system controlling the operation of the magnetic traction increaser device according to the present invention.

With reference to the accompanying drawing a specific embodiment of the present invention will be described in detail. A railway vehicle, such as a locomotive, is provided with a brake line 1 which is connected to a source of compressed air, not shown, and is a part of the brake control circuit. Also passing through the vehicle is an air pipe 2 which extends through the locomotive and may have at its end flexible hoses with couplings for connection to mating couplings on adjacent vehicles.

The brake line 1 is connected through line 3 to a brake control valve 4. The air pipe 2 is connected through a check valve 5 to an air supply container 6.

The brake control valve 4 is connected to an auxiliary compressed air reservoir 7 and is operable to control the air delivered to a pressure converter 8 through a line .9. The pressure delivered through the line 9 is dependent upon the pressure in the brake line 1. The line 9 communicates with two cylindrical spaces 12 and 13 in the pressure converter in which are mounted pistons 10 and 11. The opposite side of piston 11 is subjected to the fluid pressure in a cylindrical chamber 14 and there is also a spring 15 acting upon the same side of the piston. The piston 11 is mounted on one end of a piston rod 16 whose upper end is engageable with the piston 10 connected to a piston rod 17 which has at its upper end a piston 18. The pistons. 10 and 18 actuate a double valve 19 and 20 which controls the air delivered from the air supply container 6 and also the discharge to the atmosphere of air from the cylinder 21 in which the piston 18 moves.

A line 22 leads from cylindrical space 21 to a brake cylinder 23 having a movable piston therein and a piston rod which is connected to the brake mechanism, so that when fluid under pressure is supplied tobrake cylinder 23 the brake shoes will be applied against the wheels of the vehicle (not shown). A pressure responsive switch 25 is also connected to the line 22 and actuates a switch comprising electrical contact 24.

A conduit 26 is connected between air supply container 6 and two magnetic valves 27 and 28 which may be opened to discharge to the atmosphere. Magnetic valve 27 controls the supply of air to a conduit 29 which is also connected to an inlet port 30a of a magnetic valve 30. In addition, the conduit 29 is connected through a throttle valve 31 to head spaces 32 and 32' in fluid pressure motors 33 and 32' so that when a pressure is applied in these spaces the motors will be lowered.

The other sides of the fluid motors have crank spaces 34 and 34' which actuate the fluid motors in the upward direction and are similarly connected through a throttle valve 35 to the magnetic valve 28. In the nonenergized state, the magnetic valves 27 and 28 will open the cylinder spaces 32, 32' and 34, 34' to the atmosphere through the openings 27a and 28a, respectively.

The magnetic valve 30 is provided with a second inlet port 30b which connects a line 36 leading from air conduit 26 to a conduit 37 which communicates with the cylindrical chamber 14 of the pressure converter 8. The line 36 is connected with conduit 37 when the valve 30 is not energized, but when energized the valve connects the conduit 29 with the conduit 37. Also connected to the conduit 37 is a fluid pressure responsive switch 39 which actuates an electrical switch 38.

Connected to the piston rods of fluid pressure motors 33 and 34' is a magnetic traction increaser device 40 which is movable vertically between effective and ineifective positions with respect to the upper surface of a rail 42. The magnet 40 is provided with an actuating arm 4011 which is engageable with a snap switch 41 which is normally held by means of a spring against contact 41a as shown in the drawing. When the magnet is lowered to its effective position by the fluid pressure motors, actuating arm 40a will engage switch 41 to throw the switch to the other contact 41b.

The cylinders of the fluid pressure motors 34 and 34' are also provided with springs 48 and 48' which are pretensioned to counterbalance the weight of magnetic device 40.

A source of electrical energy indicated at 43 has one side connected to ground and the other side connected to a contact of switch 24. The other contact of switch 24 is connected to a relay switch 44 and to the solenoids of the magnetic valves 27, 28 and 30. The solenoids of the magnetic valves 27 and 28 are also connected to the contacts 41a and 41b, respectively, of the snap switch 41 whose movable switch arm is connected to ground. The solenoid of magnetic valve 30 is also connected to ground.

The outlet contact of switch 24 is connected by an electrical lead 45 to a switch 46 which when closed bypasses the switch 24. Electrical switch 38 is in a circuit 47 which functions to disconnect the vehicle propulsion mechanism when the propelling or driving force attains a maximum value.

The drawing illustrates the various components in their positions when the traction increaser device is inactive. In this position the brake control valve 4 will not admit any air under pressure to line 9 and the pressure converter 8 will prevent air being delivered to the conduit 22 from air supply container 6. The magnetic valve 30 is deenergized and fluid under pressure is transmitted from line 36 across valve 30 totubular conduit 37 into the cylindrical chamber 14 of the pressure converter 8. Electrical contacts 24 and 38 are opened and the magnetic valves 27, 28 and 30 are not energized. There is no fluid pressure in any of the cylindrical spaces 32 and 32' and 34 and 34'. The magnet 40 is deenergized and is retained in its elevated or ineffective position by springs 48 and 48'.

Operation When it is desired to brake the vehicle the operator will actuate the brake control valve 4 so that air under pressure is delivered through line 9 and to the cylindrical spaces 12 and 13. This initial or preliminary braking pressure will substantially correspond to the pressure drop in brake line 1. However, the pressure acting against piston 11 within the cylindrical chamber 14 through the conduit 37 will maintain the piston 11 in its lowermost position as shown in the drawing. However, the piston 10 will be moved upwardly under the influence of the air pressure introduced through line 9 to open slightly the double valve 19, 20 so that a corresponding low braking pressure is maintained in the cylindrical space 21. This low pressure acts upon brake cylinder 23 to apply a relatively low braking force. However, the pressure in conduit 22 is suflicient to actuate fluid pressure switch 25 to close contacts 24. As a result, relay 44 is energized and the magnetic increaser device 40 is connected to the source of electrical energy 43 to become energized. In addition, magnetic valve 27 is energized through snap switch 41 and the magnetic valve 30 is energized. The energized magnetic switch 27 admits air under pressure into conduit 29 and through the inlet port 3001 of the energized magnetic valve 30 to cylindrical space 14 of the pressure converter '8. Thus a low braking force will be applied against the vehicle wheels.

A pressure differential will be established across throttle valve 31 which will increase the pressure in cylindrical spaces 32 and 32' sufiiciently to overcome the force of springs 48 and 48. As a result, traction increaser device 40 will be lowered toward the rail 42 into its efiective position. The lowering of the traction increaser device 40 to its effective position causes the actuating arm 40a to move the snap switch 41 against contact 41b. The result will be to deenergize magnetic valve 27 and to energize magnetic valve 28. The deenergization of magnetic valve 27 will open the conduits 29 and 37 together with the cylindrical space 14 and the fluid motor pressure spaces 32 and 32' to the atmosphere. The energization of valve 28 will admit compressed air to the throttle valve 35 so that a pressure differential established over the throttle valve will increase the fluid pressure in cylindrical spaces 34 and 34' of the fluid motors. The energization of the magnetic device 40 will establish a magnetic field between the magnet 40 and the rail 42 to increase the force exerted by the wheels upon the rails. The result will be increased traction or adhesion of the wheels on the rails.

As air under pressure is withdrawn from the cylindrical chamber 14 of the pressure converter and evacuated through the atmosphere through conduit 37, the piston 11 will move upwardly under the action of pressure in line 9 acting in space 13. The piston rod 16 will engage piston 10 and the combined forces exerted by pistons 10 and 11 will open further valve 20, thereby increasing the pressure in the cylindrical chamber 21. This increase of pressure will be transmitted through conduit 22 to brake cylinder 23 and a greater braking force will be applied to the wheels of the vehicle.

In order to release the brakes, the brake controller valve 4 is moved to its release position and the air under pressure is evacuated from line 9 to the atmosphere. Opening of conduit 9 to the atmosphere in turn empties compressed air from pressure converter 8, conduit 22 and the brake cylinder 23. With pressure no longer acting in the conduit 22 the pressure responsive switch 25 will be opened, thereby deenergizing magnetic valves 27,

28 and 30. At the same time, relay switch .44 will be deenergized to disconnect the magnetic device 40 from the source of electrical energy 23. The deenergization of magnetic valve 30 will connect the conduit 37 with line 36 which has the effect of switching pressure converter 8 into the position for the application of a low or weak braking force. With the deenergization of magnet 40 there will be no longer a magnetic field between the magnet 40 and the rail 42. Thus, the springs 48 and 48 with help from the increased pressure in the chambers 34 and 34 through throttle valve 35 will lift the magnet 40 to its ineffective position. Raising ofmagnet to the ineffective position will cause the switch 41 to snap back into the position shown in the drawing under the action of a spring.

In the event that braking action is initiated but the traction increaser device remains ineffective because of some malfunction, such as an interruption of electrical energy, the magnetic valves 27, 28 and 30 will remain deenergized. The cylindrical chamber 14 of the pressure converter 8 will be under pressure from conduit 36 during the entire braking operation and as a result a low braking force will be transmitted to the wheel brakes.

Should the magnetic device 40 not be lowered at the beginning of the braking operation because of damage or malfunction to its. supporting structure even though air under pressure is admitted to the cylindrical chambers 32 and 32, it is apparent that the snap switch 41 will remain in its uppermost position as shown in the drawing during the entire braking operation. The magnetic valve 27 will remain energized and will deliver compressed air through lines 29 and 37 to the cylindrical chamber 14 of the pressure converter. Thus, in this condition also, a low braking force will be transmitted to the wheel brakes. This feature of the present invention is important since failure of the traction increaser device will not cause wheel slippage as a result of too strong an application of the brakes.

As long as the traction increaser device 40 remains in its ineffective position, switch operator 39 will keep the switch 38 continually in its open position and, accordingly, the circuit 47 will be open. It will thus be possible to exert only a reduced driving effort by the wheels upon the rails.

When it is desired to increase the driving force during low speed such as when the locomotive is starting, the switch 46 will be closed and the magnetic valves 27, 30 and the magnetic increaser device 40 will be energized. Upon the energization of magnetic valves 27 and 30, compressed air will be admitted to conduit 37 through line 29 and there will be sufficient pressure in the switch operator 39 to open contact 38. After the increaser device 40 has been lowered to its effective position and snap switch 41 actuated to its lowermost position the conduit 37 will be connected to the atmosphere through deenergized magnetic valve 27. The decrease in pressure of conduit 37 will cause the switch operator 39 to close contact 38. Since magnetic valve 28 has been energized, a pressure will be built up in the cylindrical chambers 34 and 34' and the action of the magnetic device 40 will increase the traction of the vehicle wheels upon the rails. Thus it will not be possible for any sudden acceleration to occur because of the increased driving force. Since the conduit 37 will become empty of compressed air only when the traction increaser has functioned to close contact 38 through its operator 39, the driving force will remain decreased in the event of any damage to the traction increaser device. As a result, sudden acceleration of the vehicle wheels will be prevented.

It will be apparent that various modifications of the apparatus as described above are possible for particular conditions. In one such modification which is particularly adapted for railway vehicles which are not selfpropelled would be to omit the pressure control switch operator 39 and contacts 38. Line 36 would then be connected directly to lines 9 or 22 and not to the air supply container 6 as described above.

The magnetic traction increaser device disclosed in the present invention is of the electromagnetic type. However, it is possible to employ a known type of traction increaser having a permanent magnet.

A railway vehicle may be equipped with several of the traction increasers as described above. A suitable serial switching circuit may be provided to enable the pressure converter 8 and switch contacts 38 to be actuated for strong braking force or high propulsion effort only after all traction increasers are operative, i.e., in their effective position and energized.

The traction increaser according to the present invention may also be employed in those railway vehicles whose wheels are braked electrically. In such vehicles, the pressure of the compressed air in the conduit 37 is delivered to a switching device associated with the pressure converter 8 to control the application of the braking force.

Thus it can be seen that the present invention discloses an improved forrn of control arrangement fora magnetic traction increaser device employed on a railway vehicle. The arrangement includes several features which safeguard the operation of the traction increaser sothat skidding of the wheels is prevented either during, braking or during initial application of the driving power to the wheels of the vehicle.

It will be understood that this invention is subject to modification in order to adapt it to different uses and conditions.

What is claimed is:

1. In a wheeled vehicle having wheels operating on a metallic supporting surface, the combination of a magnetic traction increaser device movable between effective and ineffective positions, means for lowering said device to the effective position, means for raising said device from the effective position to the ineffective position, electrical. control circuit means for controlling the operation of said device raising and lowering means, and means responsive to the effective position attained by said device for exerting a force against said device while the device is still in the effective position to urge said device away from its effective position but prior to actuation of said raising means.

2. In a wheeled vehicle as claimed in claim 1 with there being switch means in said control circuit and actuated by said device in its effective position to operate said force applying means.

3. In a wheeled vehicle as claimed in claim 2 and further comprising means in said electrical control circuit and responsive to the actuation of said switch means for stopping the operation of said device lowering means whereby said device is no longer urged to its effective position.

4. In a wheeled vehicle as claimed in claim 1 with said raising and lowering means comprising a pair of double acting fluid motors with both ends thereof connected to a source of fluid under pressure, first valve means connected between the lowering ends of said fluid motors and said fluid pressure source and second valve means connected between the raising ends of said fluid pressure motors and said fluid pressure source, and actuating means in said electrical control circuits for said first and second valve means and responsive to said switch means, said switch means operatively connecting said first valve actuating means in said electrical control circuit when said device is in its ineffective position and operatively connecting said second valve actuating means when said device is in its effective position.

5. In a wheeled vehicle as claimed in claim 4 with said fluid pressure motors having pretensioned spring means exerting a force on said magnetic device away from its effective position greater than the weight of said device.

6. In a wheeled device as claimed in claim 4 with said valve means comprising magnetic valves having solenoids therein, said switch means comprising an electric snap switch operatively connected to said magnetic valve solenoids.

7. In a wheeled vehicle as claimed in claim 1 and further comprising a wheel braking mechanism, and regulating means operatively connected to said wheel braking mechanism for decreasing the braking force exerted in response to an increase in the force exerted by said device lowering means in urging said device toward its effective position.

8. In a wheeled vehicle as claimed in claim 7 with said braking mechanism being fluid pressure actuated and connected to a source of fluid under pressure, and a magnetic valve interconnected between said brake regulating means and said source of fluid pressure and responsive to the deenergization of said magnetic traction increaser de vice to decrease the braking force.

9. In a wheeled vehicle as claimed in claim 4 and comprising a fluid pressure braking system for the wheeled vehicle and connected to a source of fluid under pressure, means connected to said braking system for regulating the fluid pressure delivered thereto to vary the braking pressure, and means responsive to the fluid pressure actuating said braking mechanism for energizing said mag netic traction increaser device and for actuating that one of said first and second valve actuating means which is connected in circuit by said switch means.

10. In a wheeled vehicle as claimed in claim 9 and further comprising means carried by said vehicle for driving the wheels thereof, and means responsive to the fluid pressure actuating said braking mechanism for reducing the driving power to the vehicle wheels when a braking pressure is delivered to said braking mechanism.

11. In a wheeled vehicle, as claimed in claim 10 and further comprising selectively operable means for bypassing said power reducing means to increase the driving power delivered to the wheels.

12. In a wheeled vehicle as claimed in claim 10, with said vehicle having a plurality of magnetic traction increaser devices, and means operatively connected to said wheel driving means and said braking pressure regulator for selectively maximizing one of said driving means and said braking means only when all of said devices are effective.

References Cited UNITED STATES PATENTS 1,661,622 3/1928 Pieper 188165 X 1,790,202 1/1931 Down 188-165 X 2,270,425 1/1942 Farmer l88l65 X DUANE A. REGER, Primary Examiner U.S. Cl. X.R. 303--3 

